Q: What is a
nudibranch?A: A sea slug; "branch" (slang); naked
snail; members of the subclass Opisthobranchiata belonging to the
class Gastropoda in the Phylum Mollusca; a suborder of molluscs
lacking a shell as adults and having external respiratory
appendages usually on the dorsal surface. Their taxonomic
classification is as members of the class Gastropoda,
subclass Opisthobranchia, order Nudibranchia.

Q: What's
so great about these critters?
A: They are probably the most beautiful creatures in the ocean!
There are over 3000 species worldwide- they're fascinating, easy
to follow once found, and make great photography subjects. They
don't bite you, emit a foul odor, sneak up behind you, or
otherwise ruin your day. They don't make good pets so they're not
over-collected by divers, but they are rare enough to command
your attention when seen. When you see a variety you haven't seen
you never know if it's one that has been taxonomically classified
and given a species name, or one that nobody has had the
opportunity to classify (another good reason to take a
photograph!)

Q: How big are they?
A: Most are small, about 1-2 inches or less, though some species
such as the Spanish dancer may grow up to 19 inches in length or
more. If you search for them under rocks, you are more likely to
encounter the smaller variety; if you scan the reef underwater
from a distance, you are more likely to see a brightly colored,
larger species. If you slowly scan the reef from a very close
distance (2-3 feet), you are more likely to encounter the
well-disguised variety that utilizes protective coloration to
disguise itself against the background of the coral reef and
algae.

Q: Where do
nudibranchs live?
A: In the ocean, exclusively. Most live near the shore, in tidal
pools, and in shallow waters readily accessible to the scuba
diver. I have never seen one diving in the Caribbean (though I
have seen colorful snails with shells, such as flamingo
tongues). They are prolific throughout the Indo-pacific region,
the west coast of the U.S., Hawaii, and Guam, to name a few of
the Pacific ocean regions they populate.

Q:
Can I collect them for my salt-water aquarium?
A: Nudibranchs don't survive long at all in an aquarium, because
of their special diets. When was the last time you saw one in a
public aquarium? What about in a tropical fish store? What about
mounted on the wall as a trophy? As preserved specimens, they
lose their color and shape. The best way to view them is in their
natural habitat, and the best way to remember them is through
photographs.

Q: How do
nudibranchs reproduce?
A: Nudibranchs are hermaphroditic, meaning they possess both male
and female sex organs. Mating nudibranchs exchange sperm through
a common aperture, a protruding tube on the side of their body
which joins a similar aperture on the mating partner. Eggs are
laid in rose-like egg masses in the dorid nudibranchs, as
compared to tube-like egg strings in the aeolid nudibranchs.
Incubation of the eggs can be up to 50 days, but normally is much
shorter.

Q:
What is the difference between dorid nudibranchs and
aeolid nudibranchs?
A: Both are suborders of the order Nudibranchia, with
aeolids (a.k.a. eolids) being a type of nudibranch possessing ceratarather
than a feather-like external gill on the back and no rhinophoral sheath.
Most of the photos shown on my page are dorid nudibranchs, as are
most of the species I have encountered. Generally, aeolids are
longer and thinner, and dorids are shorter and fatter. Dorid
nudibranchs are named for the sea goddess, Doris, daughter of
Oceanus and mother of the Nereides. Aeolids are named after the
Greek god, Aeolis, god of the wind.

Q: How do
you find nudibranchs?
A: I think the best way is to pay careful attention to the
details of the reef while scuba diving-- meaning staying 2-3 feet
from the reef, slowly moving, and carefully observing for
nudibranchs. Another good place to find small nudibranchs is
underneath rocks or debris. Coral heads are great for nudibranchs
since they are populated with sponges, tunicates, anemones,
individual corals, hydroids, and other nudibranch food.Click
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